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As one of the most popular beverages in the world, a large amount of coffee wastes known as the spent coffee grounds (SCGs) is generated daily. In this study, we report a polylactic acid (PLA) composite filament with a high loading of oil-extracted spent coffee grounds (Ox-SCGs) up to 20% by weight and is three-dimensional (3D)-printable with a commercially available consumer-level 3D printer. The Ox-SCG-loaded PLA was found to be able to increase impact energy absorption. As a result, the PLA/Ox-SCG composite exhibited a 418.7% increase in toughness with a measure of 25.24 MJ/m3 at a 20 wt % Ox-SCG loading and only a 26% storage modulus reduction from the 100% PLA specimens at room temperature. The experimental results indicate that as a waste product from human consumptions and post biodiesel extraction, the Ox-SCG is proven to be a promising additive for composite property modification. The Ox-SCG can not only increase the impact toughness but also reduce the cost of overall 3D-printing materials.

We present a smartphone optosensing platform (SOP) using a digital versatile disc (DVD) diffraction grating for rapid in-field detecting neurotoxins. The smartphone holder and sample holder were 3D printed for the SOP. A DVD grating is demonstrated for the first time in a low-cost miniature spectrometer on the SOP to quantify the concentrations of neurotoxins. The SOP is capable of detecting optical absorbance spectra within the entire visible spectral range from 400 to 700 nm with the spectral resolution of 0.2521 nm/pixel. We demonstrated the performance of the DVD grating compared with a commercial transmission grating on the SOP and a conventional microplate reader. Paraoxon, as the selected neurotoxin model, is assayed by two types of cholinesterase (ChE) on our SOP, respectively. Integrating a DVD grating in the SOP allows quantification of paraoxon in the range from 5 nM to 25 μM with the detection limit of 2.9 nM. In addition to the low assessed detection limit at medically relevant concentrations, the performance of SOP with DVD gratings provides new avenues for a point-of-care toxin diagnosis with time and cost savings.

A rapid and efficient ultrasound-promoted one-pot synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] derivatives is described here. The reaction of substituted phenylhydrazine and dialkyl acetylenedicarboxylate with substituted isatin and malononitrile is catalyzed by l-proline to give good-to-excellent yields in water/ethanol (v/v, 1:1) at room temperature.

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